Patent Number: 6,528,805

Title: Dose monitor for plasma doping system

Abstract: Plasma doping apparatus includes a plasma doping chamber, a platen mountedin the plasma doping chamber for supporting a workpiece such as asemiconductor wafer, a source of ionizable gas coupled to the chamber, ananode spaced from the platen and a pulse source for applying voltagepulses between the platen and the anode. The voltage pulses produce aplasma having a plasma sheath in the vicinity of the workpiece. Thevoltage pulses accelerate positive ions across the plasma sheath towardthe platen for implantation into the workpiece. The plasma dopingapparatus includes at least one Faraday cup positioned adjacent to theplaten for collecting a sample of the positive ions accelerated across theplasma sheath. The sample is representative of the dose of positive ionsimplanted into the workpiece. The Faraday cup may include a multi-aperturecover for reducing the risk of discharge within the interior chamber ofthe Faraday cup. The Faraday cup may be configured to produce a lateralelectric field within the interior chamber for suppressing escape ofelectrons, thereby improving measurement accuracy.

Inventors: Fang; Ziwei (Sunnyvale, CA), Goeckner; Matthew (Plano, TX)


International Classification: H01J 37/32 (20060101); H01J 037/244 ()

Expiration Date: 03/02015